Just wondered if anyone could recommend a decent, well-constructed outdoor cat run. It's actually going to be for my ferrets, but there are many more cat people here than ferret people, so I thought it might be a safer bet.

I currently have a 6' x 4' run which I built with a roof, 3 solid walls and one mesh wall (see attached pictures), so would be looking for something similar but bigger as have more ferrets now than I did when I built the current one. I've seen a few on ebay, but wondered if anyone here had any experience in getting something for their cats. I would be painting and putting in some extra sleep boxes and climbing furniture once built.

Any recommendations of manufacturers/sellers/websites would be much appreciated.